Yousif A. Elhassaneen^1,, Mai A. Garib¹, Tarek M. Abd El-Rahman¹, Olfat S. Abd El-Moez¹

Agro-industrial food wastes, including onion peels and cauliflower leaves, are rich in bioactive compounds like polyphenols, carotenoids, flavonoids, and polysaccharides. This study prepared colored extracts from these wastes and evaluated their bioactive contents and application in sugar confectionery products, Bonboni and Lolypup. Onion skin ethanolic extract (OSE) exhibited higher total phenolics (397.67 ± 9.88 mg GAE/g) and flavonoids (39.11 ± 3.14 mg resveratrol equivalent/g), while cauliflower leaves aquatic extract (CLA) contained higher carotenoids (131.17 ± 8.12 mg rutin equivalent/g) and polysaccharides (116.12 ± 7.15 mg starch/g). Anthocyanin contents were similar in both extracts. CLA also showed higher lutein (81.43 ± 6.09 mg/g) and alkaloids (15.73 ± 1.04 µg atropine/g), whereas OSE had more terpenoids (34.21 ± 3.04 µg/g). Incorporating these extracts into Bonboni and Lolypup significantly increased bioactive compound levels compared to controls. Antioxidant activity tests revealed high antioxidant percentages for OSE (89.21%) and CLA (90.65%), though synthetic standards BHT and α-tocopherol exhibited superior activity. Fortified sweets showed enhanced antioxidant activity which recorded 47.69% and 51.83% for Bonboni + CLE and Lolypup + OSE than the controlled samples. β-carotene bleaching and DPPH assays confirmed moderate antioxidant effects of the extracts and products, with IC50 values indicating reduced activity after incorporation. Microbial analysis demonstrated that adding extracts suppressed bacterial and fungal growth during 60 days of room temperature storage, with total plate counts increasing to 1232±38 cfu/g for Lolypup + OSE versus 2780±45 cfu/g in controls. Sensory evaluation showed improved appearance, color, taste, odor, texture, and overall acceptability in enriched products, with Bonboni + CLA achieving top scores (appearance 9.12 ± 0.07, texture 9.17 ± 0.20, acceptability 9.13 ± 0.06). These results support the valorization of agro-industrial wastes as natural functional ingredients to enhance food quality and shelf life.

Onion skin, cauliflower leaves, bioactive compounds, biological activities, sugar confectionery, microbial analysis, Sensory evaluation